Asian Journal of Water, Environment and Pollution,Yol.5, No. 2, pp. 13-18.
A Case Study on Bulking Problems in Paper Recycling Effluent Treatment Plant in Malaysia Ghufran Redzwan*, Lisa Lee Siew Yingl, Shaliza lbrahiml and Suffian Annuar
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Programme of Science and Environmental Management, ISB-Faculty of Science University of Malaya, 50603 Kuala Lumpur, Malaysia llnstifute of Post Graduate Studies University of Malaya, 50603 Kuala Lumpur, Malaysia ffi
[email protected]
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Received December 23, 2006; revised and accepted August I 2, 2007
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Abstract: This study was conducted to investigate the cause of bulking problem at the effluent treatment plant (ETP) of a paper recycling plant in Malaysia. Hypothetically, the effluent is lacking nutrients and could induce the overpopulation of filamentous bacteria, and further cause the bulking problem during the effluent treatment using activated sludge process. Experiment to simulate treatrnent operations had been set up at laboratory. The simulation showed that the bulking started to occur after the first cycle of the fed-batch operation with the typical effluent. To make up the lacking of nutrients in the effluent, urea (N) and phosphate (P) were added as supplements with the ratio of BOD : N : P equal to 100 : 1.0 : 0.7. The supplemented effluent was again tested by a simulation study and showed thatthe bulking problem started to takeplace after the third cycle of feeding regime. Bulkingproblem also periodically took place in the actual operation when the same supplemented formula was applied; however the frequency of occurrence was lesser. Therefore, this study has shown that other than the lack ofnutrients, there are other factors that could cause bulking problem.
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Key words: Recycled paper mill effluent, activated sludge process, bulking, filamentous bacteria, nutrients supplement.
Introduction !
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have the production capacity of more than 100, 000 per year.
MT
Despite the lingo for paperless office by advances in
Pulp and paper industry is known to consume
information technology, the demand for paper still and paperboard demand was at 313.3 million metric
tremendous amount of water, which has been ranked as third, aftertheprimarymetals and the chemical industries (UMDO, 1993). The demand for water in this industry
tonnes (MT) in the year 2000 and the demand growth in Asia has been anticipated to account for a third of the
process is changed. The water consumption varies
continues to be strong. The fact is that the world paper
world's paper consumption within the next 15 years (MPPMA, 2002).It is predicted that the demand for the paper in the region will grow at an annual average of 6% to l|Yo over the long term. Keeping up with the demand for paper, 20 paper mills have been set gp in Malaysia (Sveriges Ambassad, 2004). Five ofthese plant operators *Corresponding
Author
will remain high until the principle for manufacturing with the type of paper being produced and the total consumption could reach as high as 60 m3 per MT of paper produced. From this fact, in some paper mills in Malaysia, the demand for water could be estimated reaching at 20,000 m3 per day. With such high amount of water consumption, high quality of treated wastewater is necessary. Discharge of non-compliance effluent will give significant impact to the receiving water body by the high amount of pollutant loading.
